Add missing test file to tracing:unit_tests

components/tracing/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 component("tracing") {
   sources = [
     "child_memory_dump_manager_delegate_impl.cc",
     "child_memory_dump_manager_delegate_impl.h",
     "child_trace_message_filter.cc",
     "child_trace_message_filter.h",
@@ skipping 33 matching lines @@
 
   deps = [
     "//base",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
 
   sources = [
+    "child_trace_message_filter_unittest.cc",

[Primiano Tucci (use gerrit), 2016/05/19 17:06:33]

FYI in gyp they seem excluded for IOS.
But I guess gn for IOS is not a thing yet and somebody else will have to deal
with that?

     "graphics_memory_dump_provider_android_unittest.cc",
     "process_metrics_memory_dump_provider_unittest.cc",
   ]
 
   deps = [
     ":tracing",
     "//base/test:test_support",
+    "//ipc",
+    "//testing/gmock:gmock",
     "//testing/gtest",
   ]
 
   if (!is_android) {
     sources += [ "trace_config_file_unittest.cc" ]
     deps += [ ":startup_tracing" ]
   }
 }